Wow on the tanks - that's like 8000 gallons. With the right place to put them, and some heavy dickering on the price, and a capable boiler - I would give one of those some thoughts. The dickering would need to be VERY heavy though.
I was checking out the NSP site just last week about time of day, actually. They have come around a bit - I have thought about getting into time of day rates, or seeing if I could with this setup but still not convinced. They used to be strict about having a real 'ETS' system in order to get them, for one thing - their wording about that seems to be more relaxed now. Would have to ask them to know for sure - I would just need to add a timer & plumb in one new short pipe with a zone valve in it to heat all my storage with my electric boiler when I wanted to. But there are strings attached. The base rate goes from $10 to $18/mo, for one thing - then this time of year, your consumption at 'normal' hours (7am-12pm, 4pm-11pm, or thereabouts) is at $0.03/kwh more. (0.18 vs. 0.15). TOD rates are 0.08, 11pm-7am or so. My monthly bill is only around 100 total right now (not using electric boiler). I might be better off just putting in a mini-split if I wanted to heat more using electricity, although wouldn't be as comfortable - even burning electricity with $0.07/kwh cheaper TOD rates will still be expensive with an electric boiler. I think I'll try to hit up a homeshow that they are at this spring, and put the questions to them. A timer on the hot water heater in the summer would save too - but that only costs me in the area of $25/mo anyway. So would only save in the area of $10-15/mo - vs. 0.03 more on non-TOD use plus $8/mo more base charge.
They have also changed up their PV/net metering stuff since I looked last. They will actually buy back excess production at the end of the year, at standard rates. Something else to quiz up on at a homeshow - I don't think there are any incentives.
. As to the question on DHW, I have an Indirect tank which was recently tied to my thermal storage and use my propane boiler as a back up for it. A few points from my end of the world: 1. Indirect Tanks are surprisingly very expensive 2. The high water temperature required creates challenges of its own (I use low flow/design temps to heat the house which would never heat DHW) 3. Having DHW tied to my thermal storage I see: a. how much energy they lose just sitting there b. how many times a day it needs to be brought back to temp )previously it was obviously using a lot of propane that I just did not pay much attention to). Not sure what I would do if I was starting from scratch, I would definitely investigate the "on-demand" DHW heaters. Not sure if they are good or bad, took my plumbers advice at the time. Knowing what I know now I would do my own research and come to my own conclusion.
